Stimuli previously associated with threat capture attention even when task-irrelevant and non-salient. The current study used functional magnetic resonance imaging (fMRI) to examine the neural mechanisms of attentional capture by an aversively conditioned stimulus following classical conditioning with mildly painful heat stimulation. In each trial of a training phase, either a red or a green circle was presented, one of which was followed by an aversive heat pulse on some trials (CS+). The other colour circle was never paired with a heat pulse (CS-). In a test phase, participants searched for a shape singleton. On a subset of trials, one of the distractors appeared either in the colour of the CS+ or in the colour of the CS-. Participants completed nine brain scans, including two runs of the training phase, three runs of the test phase, an anatomical scan, and then a third training run followed by two more runs of the test phase. Behavioural results revealed that response times were generally faster on CS- trials, especially during the runs immediately following training. To probe the neural correlates of distractor processing, we contrasted trials in which a CS+ distractor was present to those with a CS- distractor. The CS- distractor evoked a significantly stronger blood oxygenation level dependent (BOLD) response in regions of extrastriate visual cortex, the right inferior frontal gyrus, right temporoparietal junction, and left inferior parietal lobule. Further assessment of the trials in which a CS- distractor was present, relative to distractor absent trials, revealed a pattern of activation similar to value-driven attentional capture, suggesting that safety signals may be processed by the attention system in a similar fashion to reward cues.